I'm going to assume you mean crontab when you say 'crontable', in which case your formatting is just incorrect. Per the crontab man page (1) :
These special time specification "nicknames" are supported,
which replace the 5 initial time and date fields, and are prefixed by the '@' character:
@reboot : Run once after reboot.
The @reboot
nickname only replaces the 5 time/date fields; you still need to follow the rules on how commands are formatted in crontab (again, from the manpages):
<date fields> <user to run command as> <command to run>
E.g.,
30 12 * 8 * root touch /tmp/file
So if you want to use the @reboot
nickname, all you should be replacing are the five time/date fields at the beginning of the string, e.g.
@reboot root touch /tmp/file